Aromatic polyesters that form optically anisotropic melts and can be melt-spun into oriented filaments are disclosed in U.S. Pat. No. 4,118,372. The filaments can be heat treated to high tenacity and modulus. The polyesters are prepared primarily from para-oriented dihydric aromatic compounds and para-oriented aromatic dicarboxylic acids.
The use of selected aromatic monoand diketodiols and aromatic dicarboxylic acids in the preparation of polyesters that are optically anisotropic in the melt and can be melt-spun into oriented fibers is disclosed in U.S. Pat. Nos. 4,269,965; 4,245,082; and 4,226,970.
It is an object of this invention to provide novel polyesters. Another object is to provide such polymers that form anisotropic melts and that can be melt-spun into filaments having a high as-spun modulus. A further object is to provide such filaments that can be heat treated to high tenacity and modulus. Other objects will become apparent hereinafter.